Amorphous Si-C-O Compounds/Exfoliated Graphite Composites forNegative Electrode Materials of Lithium Ion Battery

摘要

Cross-linked silicone coatings were formed on the graphite flakes of exfoliated graphite (EG) and they were transformed toamorphous Si-C-O compounds by 1 h treatment at 1000-1350°C in argon. Charge/discharge characteristics of formedamorphous Si-C-O compounds/EG composites as negative electrodes of lithium ion battery were measured. The compositeformed at 1300°C showed large capacities of 680 mA h g-1 at 50 mAg-1 and 600 mA h g-1 at 100 mA g-1 without hysteresisexcept for the 1st charge. Due to large capacities at the 1st charge the coulomb efficiencies of the 1st cycle were 60-70%depending on the current density but after that the efficiencies were nearly 100%. Capacities of composites formed below1300°C were larger than those of 1300°C product but continuously decreased with increasing number of cycles. Thesecomposites are promising negative electrode materials of lithium ion battery by reducing the 1st charge capacity.